Technische Universitat Chemnitz, Institut fur Physik, D-09107 Chemnitz, Germany

摘要

A number of oaxis oriented MgB2 thin films were grown in-situ by pulsed laser deposition (PLD) on AI2O3-R cut, and the pinning properties were investigated using transport, DC magnetisation and magneto-optical imaging (MOI) techniques. It was found that at temperatures below 10K and large applied DC magnetic fields, the irreversibility line of/"-situ MgB2 thin films is higher that a bulk material. The critical current density Jc of in-situ thin films is less dependent on the applied magnetic field B than the current density Jc of an ex-situ MgB2 film or bulk. The penetration of magnetic field inside the film is uniform, and it follows the theoretical prediction for a homogenous thin film.